A device of this kind is known from the brochure
"Camino Neurosurgical Products" of Messrs Camino Laboratories, San Diego, Calif., U.S.A. PA1 Inside page 1:
The Camino ICP Monitoring KIT.
The device shown serves for the insertion of a probe in the form of a catheter which measures the brain pressure in the tissue and which, after a screw has been fixed in the cranial perforation, is inserted through the protective flexible tube and the screw passage bore into the brain tissue to the required scanning depth. The probe in this known construction has an adequate natural rigidity to enable it to be advanced while being aimed toward the target without any deviations in the direction predetermined by the passage bore. When the insertion position is reached, the probe is fixed on the screw by a pinch seal, with sterile closure of the passage bore. In this construction, the protective flexible tube provides only protective action against lateral incursions on the probe. An electric coupling plug provided at the proximal end of the probe is rigidly connected only to the probe, which in the known construction has sufficient resistance to tension.
The known device offers the possibility of providing a patient with a brain probe over a relatively long period, the brain being protected against infection and the external part of the probe being movable arbitrarily, for example in the event of the patient's shifting, without any risk of electrical malfunction.
There has long been the need to carry out long-term measurements of the tissue pO2, i.e., the oxygen partial pressure in the tissue, in the brain. Probes in the form of catheters suitable for the purpose are available, e.g. Clark type oxygen measuring probes. Probes of this kind suitable for use in brain tissue, however, must be extraordinarily thin and highly flexible, since otherwise they cannot follow the tissue movements during the natural movements of the brain (respiration, pulse beat) and they would injure the tissue. On the one hand, injuries of this kind are harmful to the brain and on the other hand they falsify the oxygen measurement.
With known devices it is not possible to introduce such probes into the brain tissue, since they do not have sufficient natural rigidity for progress into the brain tissue and because they are not sufficiently tension-resistant, so that they would break between the coupling plug and the screw in the event of movements by the patient or manipulation being carried out on the patient.